By default, quiz and poll questions only let players choose one answer. For questions where more than one answer is valid, you can choose "multi-select" from the answer options dropdown.
Now, players will be able to choose more than one answer. They will need to use a "submit" button to confirm their selection.
Multi-select is only available with select subscriptions.
On quiz questions, "multi-select" is automatically chosen if you set more than one answer as correct. If your subscription does not provide access to "multi-select", you'll need to switch this back to "single select" before you can save changes to your kahoot.
How do quiz points work with multi-select?
Players can receive up to 1000 points per correct answer selected (up to 2000 points per correct answer if points are doubled). Unless the question timer is disabled (a game option on assignments), response time will reduce actual points accrued. If players choose any incorrect answers, they get 0 points.